No, that's not a typo. I don't mean pump timING. I mean its time to break down and replace the injector pump

Today on my 20 mile commute to work is when the problems started. As I got close to work, I noticed that when I would step down on the throttle hard from a dead stop it would hesitate a split second before it would "catch" and take off. I thought that was weird, but figured that, since I'm nearing the end of running the first tank of fuel with Diesel Kleen in it, maybe the fuel filter was getting plugged up with the junk that the additive loosened up in the fuel system.

Drove it a couple of miles over to Costco and back at lunch time and it seemed OK - the hesitation was gone. Driving home tonight I got about halfway and it started acting up again, and it was getting worse. By the time I stopped at the Napa about five miles from my house to return a couple of exhaust pieces I didn't use, I was pushing the throttle over halfway to the floor just to get it started and keep it moving in stop and go traffic.

I got a new fuel filter from Napa and installed it right there in the parking lot. Bled the air out through the Schrader valve. Seemed to have good fuel flow at the filter. At this point I'd been stopped for about 15 or 20 minutes, and when I fired it up it seemed OK again. Problem solved, right? WRONG!

Within a mile or two it was right back to having to push the throttle halfway just to get the RPMs up enough to take off from a stop. Seemed like once it got up to around 2000 RPMs it got better - not good, but better. The closer I got to home the worse it got. By the time I made the last stop at the light before driving up to the top of the hill where my house is, I was having to floor it just to get it up to 1000 RPMs. Barely chugged up the hill under its own power.

We went to church, and when we got home a couple of hours later I decided to give 'er a try. Started up just fine, ran just about like it has been for the last month or so. Drove it around the neighborhood a little while and everything was fine for the first few minutes. After that it started doing the slight hesitation when I stepped on it from a dead stop. I got it home and parked it ASAP before it decided to completely quit on me.

SO, I believe it is finally time for me to break down and replace the pump. Anybody disagree with that diagnosis? Anything else that could make it behave that way until you drive it long enough to get good and warm and then get better as it cools down, and the longer it cools the better it works and the longer it works before quits again? Not likely to be the lift pump, is it? Also probably a safe bet that turning up the fuel screw ain't gonna' help, huh?

Since I have a complete spare engine, I may just swap that pump on to see how it works. Who knows, it may be a low mileage rebuild? I figure since rebuilds start at over $400 its worth a couple of hours to at least try the spare.

Good news is that when I told my wife I needed a pump and if I have to buy one it will be over $400, her reply was to say - with a smile no less - "good thing you got the truck for such a good price, huh?" Man you gotta' LOVE a woman like that!

 

CJ,

Sorry to hear the truck isn't running well. Was it smoking at all? There have been post about people pouring warm water on the pump to cool it down a bit and see if that temporarily solves the problem. This is not recommended as pouring cooler fluid on the pump can cause damage in itself to the internals of the pump and that would suck if it wasn't the problem. The reason I bring it up is when a failing pump gets warm is when people noticed them acting up similar to yours.

Swapping out the pump with your spare to see if it works will only cost you time. Weren't you also messing around with your injectors as well?

Since you are going through the trouble of building an exhaust and thinking about ram air mods to increase power, you typically want to start with a sound well running engine. I was impressed with how much better my truck ran after I swapped out the injectors and IP. If you use the old parts, you may never realize the benefits of your mods. Just my 2 cents.

 

sorry to hear about the ip but i bet you know wher to get a new one at just to bad it won't have that discout on it anymore

 

Nope, not a hint of smoke at all. That's one thing that kinda' surprised me. Its always idled a little rough, but when I was trying to limp it home it would hardly idle at all. It must've died a half a dozen times when I was trying to get it to take off from a stop. I had to "feather" the throttle up to about half open before it would even start to rev up to 750-1000 RPMs - enough to drop it back into gear and get it moving. With my foot off the throttle it would idle down to about 300 RPMs and sometimes just idle, sometimes die.

Yeah, you're right the way its acting sounds just like the symptoms others have described for a worn and failing pump that's overheating. That's where I came up with the diagnosis. Haven't tried the cool water trick yet, but I'd bet I know just what it would do. I'll try it Friday (taking the day off to work on the exhaust). I'll betcha a little lukewarm water on the pump will make it straighten up and fly right for a few minutes at a time. I'll even give ya' 2 to 1 odds. Any takers?

As for the mods, I'm thinking at this point that my pump has been slowly getting worse for the last two months. Thinking back on it that's how it seems to me anyway. Also my mileage has been kinda poor - only around 11-12 mpg - another sign of a failing pump. The lack of power and mileage is what has caused me to accelerate the pace of my mods. Just trying to get some more oomph out of the old girl. If I swap the pumps I'll be doing it lines and all, so it shouldn't take long. I'm guessing an hour and a half, tops. Figure I haven't got much to lose. If the used pump isn't up to snuff, I guess I'll probably know pretty quick.

Some may recall a post I made a month or so ago. A buddy of mine has an 83 F250 at his parent's house over in Spokane. He put a new pump and injectors on it, then drove it less than 10k miles before it dumped its oil cooler on the freeway and siezed the engine. He's going over at the end of the month and plans on pulling the pump and injectors off & bringing 'em back for me to put on my truck. Provided they're all still in good shape, I'll be giving him a couple hundred bucks for his trouble.

 

Hey now, don't rub it in

Truth is the one I bought on sale and then returned, I paid cash for it out of my "mad money" funds - that was before my wife even knew I had bought the truck. Thought I was going ot have to replace it before I could even bring the truck home.

Now if I have to buy one it will be paid for out of our car repairs fund - so I still end up with a new pump, but I get to keep my mad money for other things.

So its all good

 

I'm sad to say that your IP problems appears to be very very close to what I had on my 1985 6.9 last month.

Sudden loss of power and the the slow death of not wanting to climb the hill home, and then the stalling at idle unless the throttle was feathered and then it just didn't want to run. After sitting it would restart fine but then started rough idle etc.

I'd agree on the IP R&R. I also did the fuel return lines and later the injectors. In hind sight I'd have done the whole thing at one time, but then that's hind sight!

Good luck.

 

Thanks for the feedback Sailors30. I'll probably not be re-doing the return lines, just the o-rings. Mine were recently redone and have less than 1000 miles on them.

As for the injectors, I think I'll probably swap those from the other motor along with the pump. I already have them out of it, and I've been wanting to check my compression anyway. Seems to me like now would be the time to do it. While I have the injectors out it only makes sense change them and keep the injectors "matched" with the pump that they came with.

When I get the newer set of pump and injectors at the end of the month, If I decide to swap them in, I'll swap all those as a set as well. Thanks for the advice and reinforcement of the diagnosis.

 

my failed ip that i replaced recently had different symptoms. it would not start or engage at all when hot. if the engine was running, being hot did not seem to effect power or rpms.

j.hanna
dovfd
`90,f450,7.3l,5 speed

 

As Artie Johnson would say, "Hmmmmmn, dat es velllly interestinK!"

Guess there is more than one failure-mode. Probably depends on exactly what fails and exactly how it fails internally......

 

I'll chime in on this too. Those are not textbook pump symptoms, but I won't say it's not the pump.

Usually they run real rough and blow lots of blue smoke. Another thing they like to do is not catch themselves after a throttle snap.

 

Got another suggestion as what it could be? Anything else that you know of matches those symptoms? My buddy that has the almost new pump and injectors to sell me also started talking about a second "micro filter". He described the 8"-10" metal shell around the fuel line between the lift pump and the filter. Think that has anything to do with it? I was pretty skeptical of that idea since I had good fuel flow at the filter - even when it would barely run. If you have some other ideas, I'm all ears. You've never steered me wrong so far buddy, and I would LOVE to not have to replace the pump.

You mean like hesitating when you punch it, or do you mean dying when you lift your foot too fast? Doesn't really matter I guess - unless you mean something completely different than either of those - because when it starts acting up mine is doing BOTH of those things.....

 

sorry jeeprs i just had to say that but sounds like already have under control i myself am having pump probs but i will put a new one on with new inject yes i now have 5 idis sitting out in the lot as my wife calls it but each truck is for a diff kind of job the two i just bought will become good work trucks for the crew but first the have to get off there butts and work

 

I mean just stab the throttle in neutral. When it comes back down, a bad pump will just quit. Usually weird running is the pump though.

 

Hell man, you can't even stab mine in neutral - it dies if you do.
If you've already got the pedal down and take your foot off of it and let it come back down - it dies.

 

I don't know, sounds like it could be the IP but if its crapping out with throttle I would not rule out your lift pump. The IP will pull some fuel through the lines, and if the lift pump isn't working it can't push any fuel the IP requires as it increases with throttle. I watched a certain jackass route his fuel lines around his lift pump on a Mercedes he did a veggie oil conversion on so that the IP was pulling whatever fuel it could, and when he hit the throttle it would die.
The lift pump will cost you about $25 and a couple hours if you can hold a wrench. I would check that first, or at least the flow to ensure its working. If it ain't blowing smoke or anything but dying I'd suggest lift pump.